The present disclosure relates, in various embodiments, to a method of cleaning a particle classifier. In particular, the present disclosure relates to a method of removing particle and material build-up from the rotor and/or stator of a classifier, which may occur during classification of particle materials. While the method is described with respect to removing toner build-up that occurs during classification of toner particles, such as may be used in a photo or electrostatographic imaging apparatus, the method is amenable to removing the build-up of other particle materials that are subject to classification processes.
Particle separation of particle materials, such as, for example, toner particles, is typically accomplished by particle classification using a classifier. Classification allows for particles of a desired size and/or size to be separated from larger, unwanted particles.
One problem associated with particle classification is that material builds up at the inside of the stator ring during classification. Material build-up results from several factors including high particle velocity in the classifier, fusing properties of the particles/materials, and the relatively high temperature of the stator ring during classification. Particle/material build-up reduces the efficiency of the classification and may be a source for the generation of excessively large particles.
Because particle/material build-up on the stator ring is undesirable, periodic cleaning of the stator and classifier is required. The frequency with which the stator must be cleaned depends on the use of the classifier and the desired output. In some instances, it may be necessary to clean the classifier on a daily basis. One problem associated with cleaning the rotor or stator of a classifier is that the classifier must be opened or disassembled to clean the selected part such as by manually scraping the build-up off the stator. This results in down time in which the classifier cannot be operated. For example, maintenance time associated with removing toner particle build-up is typically on the order of about one hour.
Another problem associated with conventional classifier cleaning techniques is that the cleaning material may contaminate or pollute the particle material. Chemical cleaning solutions may leave behind a residue or may not be completely removed from the classifier such that particles processed in the classifier may become contaminated. Cleaning the rotor with small polymer particles or iron particles may also contaminate the particles being classified. Contaminated particles may not properly function in the manner in which they were intended to function.
Classifying toner particles used for electrostatographic imaging device presents still another problem. Toner screening has been switched from screening over a 75 micron screen to screening over a 44 micron screen. The reduced screen size results in reduced throughput and short screen life due to blinding.
Thus, it is desirable to provide a method for cleaning a particle classifier that reduces or eliminates the time period during which the classifier cannot be used while the classifier is cleaned. Additionally, it is desirable to provide a method for cleaning a classifier that reduces or eliminates the potential for the particles being classified to become contaminated by the cleaning material.